The present invention relates to a gene encoding a novel cell cycle control protein AIM-1 (aurora and IPL-1 like midbody-associated protein kinase), recombinant vectors containing said gene, cells transformed with said vectors, processes for producing AIM-1 using said gene and recombinant AIM-1 proteins obtained by said processes. The present invention also relates to oligonucleotide or peptide nucleic acids capable of specifically hybridizing to a nucleotide sequence encoding AIM-1 protein, antibodies recognizing AIM-1, therapeutic agents for diseases associated with abnormal cell growth comprising an inhibitor against AIM-1 protein, and screening methods for materials having serine-threonine inhibitory activity using AIM-1 gene or AIM-1 protein.
Mitosis is a fundamental mode of nuclear division of eukaryotic cells and a highly coordinated process by which eukaryotic cells assure the fidelity of chromosome segregation. The number of chromosomes is often a multiple of the basic number unique to the species, but errors during mitosis result in an individual having one to several chromosomes added to or deleted from the multiple (aneuploid), which may cause cell death or oncogenesis.
Aurora (Glover et al., Cell 81:95-105, 1995) in Drosophia (Drosophia melanogaster) and its most closely related IPL-1 (Francisco et al., Mol. Cell. Biol. 14:4731-40, 1994) in budding yeast (Saccharomyces cerevisiae) are molecules participating in M phase of mitosis and are thought to be required for high-fidelity chromosome segregation.
However, no molecules corresponding to aurora or IPL-1 have been so far reported in mammals. If a gene encoding a molecule controlling the cell cycle in mammals were available and its functions explained, it would be very interesting for pharmaceutical applications such as anticancer agents.
An object of the present invention is to search for a molecule controlling the cell cycle in mammals to determine the nucleotide sequence of a gene encoding the same, produce such a molecule by gene recombinant techniques using a recombinant vector containing said sequence, and show a potential for development of novel medicaments by constructing a screening system or the like using the same.
The inventors succeeded in isolating a gene encoding a novel cell cycle control protein kinase AIM-1 (aurora and IPL-1 like midbody-associated protein kinase) by screening a cDNA library of rats using a conserved sequence in serine-threonine kinase domain (FEBS LETT. 320:246-250, 1993) as a probe, and in explaining its functions.
Accordingly, the present invention provides a DNA containing a nucleotide sequence encoding the amino acid sequence shown as SEQ ID NO: 2 in Sequence Listing, or a nucleotide sequence encoding a protein having the amino acid sequence shown as SEQ ID NO: 2 in Sequence Listing with partial substitution, deletion or addition and having cell cycle control activity, or a nucleotide sequence hybridizing to them.
The present invention also provides a recombinant vector containing a gene encoding AIM-1 protein.
The present invention also provides a prokaryotic or eukaryotic host cell transformed with a recombinant vector containing a gene encoding AIM-1 protein.
The present invention also provides a process for producing AIM-1 protein, comprising culturing a cell transformed with a recombinant vector containing a gene encoding AIM-1 protein, and isolating and purifying the target protein produced.
The present invention also provides a recombinant AIM-1 protein produced by said process.
The present invention also provides an oligonucleotide or peptide nucleic acid capable of specifically hybridizing to a gene encoding AIM-1 protein.
The present invention also provides an antibody recognizing a peptide having at least five continuous amino acids in the amino acid sequence shown as SEQ ID NO: 2 in Sequence Listing.
The present invention also provides a therapeutic agent for diseases associated with abnormal cell growth comprising an inhibitor against AIM-1 protein.
The present invention also provides a screening method for materials having serine-threonine inhibitory activity using AIM-1 gene or AIM-1 protein.
We also tested how AIM-1 is expressed during each stage of cell division and examined the role of AIM-1 in the cell cycle.